It is. I slept on a lacrosse ball again last night. I got up in the middle of the night to pee and when I re adjusted the ball, I felt a deep pop. Not a snap, a pop. It got all warm in the area that I was hurting in. I freaked for a minor thinking I tore a rhomboid, or ruptured something, but I have no bruising or pain. It's kinda tight, but nothing painful, and no weakness.